Small changes in intake restriction make virtually NO difference because the turbo provides more than twice the air the engine ever needs and the wastegate hangs open, dumping excess boost from 1600-2000 rpm all the way out to the redline. Reducing air restriction makes virtually NO detectable difference until the retriction becomes VERY great (an air filter occluded more than about 25% will start to cause a problem and the engine will start to smoke at idle).

Marshall